Apparatus for processing photographic material or the like

ABSTRACT

Apparatus for wet treatment of photographic films has two pairs of rollers which transport films in a channel between upper and lower liquid discharging chambers. The lower roller of each pair dips into a supply of processing liquid in the first compartment of a vessel. When the first compartment is filled, the liquid overflows into a second compartment of the vessel whose capacity at least equals that of the chamber or chambers located above the maximum level of liquid in the first compartment. The chambers receive liquid from the first and second compartments by way of one or more pumps. The second compartment serves to store liquid which, on stoppage of the pump or pumps, leaves by gravity flow the chamber or chambers which are located above the maximum liquid level in the first compartment.

United States Patent 1 Geyken et a1.

[ May 28, 1974 APPARATUS FOR PROCESSING PHOTOGRAPI-IIC MATERIAL OR THE LIKE [75] Inventors: Erwin Geyken; Peter Dawidowitsch; Franz Ertl, all of Munich, Germany [73] Assignee: AGFA-Gevaert Aktiengesellschaft,

Leverkusen, Germany [22] Filed: Mar. 16, 1973 [21] Appl. No.: 342,321

[30] Foreign Application Priority Data Wanielista et a1. 95/89 R X Frick et al 95/94 R [57] ABSTRACT Apparatus for wet treatment of photographic films has two pairs of rollers which transport films in a channel between upper and lower liquid discharging chambers. The lower roller of each pair dips into a supply of processing liquid in the first compartment of a vessel. When the first compartment is filled, the liquid overflows into a second compartment of the vessel whose capacity at least equals that of the chamber or chambers located above the maximum level of liquid in the first compartment. The chambers receive liquid from the first and second compartments by way of one or more pumps. The second compartment serves to store liquid which, on stoppage of the pump or pumps, leaves by gravity flow the chamber or chambers which are located above the maximum liquid level in the first compartment.

15 Claims, 2 Drawing Figures ammgnmze m4 3.812.870

' sum 1 or 2 APPARATUS FOR PROCESSING PHOTOGRAPI-IIC MATERIAL OR THE LIKE CROSS-REFERENCE TO RELATED PUBLICATION The apparatus of the present invention constitutes an improvement over and a further development of the processing apparatus which is disclosed in commonly owned US. Pat. No. 3,688,667 granted Sept. 5, 1972 to Frick et al.

BACKGROUND OF THE INVENTION The present invention relates to apparatus for pro cessing elongated strip or sheet material, and more particularly to improvements in wet treatment of photographic films or similar sheetor strip-like materials which move lengthwise and are treated by streams of a developing, fixing, washing or other fluid.

US. Pat. No. 3,688,677 to Frick et a]. discloses a processing apparatus wherein strips or sheets of photographic material are treated during travel from a first pair toward a second pair of transporting rollers. The two pairs of rollers define for the photographic material an elongated horizontal path which extends through a channel between an upper and a lower liquid discharging chamber. The chambers are provided with orifices which direct streams of a processing liquid at an oblique angle to the plane of photographic material. The lower roller of each pair of transporting rollers dips into a body of liquid in a tank which supplies liquid to a pump serving to deliver liquid into the liquid discharging chambers. The tank is provided with an overflow opening which is located at a level above the lowermost points of the lower rollers to thus insure that each lower roller dips into the supply of processing liquid during each and every' stage of operation. Furthermore, the apparatus is provided with means for conveying the liquid from the channel onto the lower rollers to thus reduce the likelihood of splashing and the resulting oxidation of liquid in the tank.

It was found that the location of the upper level of liquid in the tank cannot be regulated with a desired degree of accuracy by the simple expedient of providing the tank with one or more overflow openings. This is due to the fact that, when the apparatus is in use, both liquid discharging chambers are filled with liquid. Since at least one of these chambers is located above the tank, the level of liquid in the tank invariably descends when the pump is started because the pump must supply liquid into the chamber or chambers which are located above the tank and are empty when the apparatus is idle. Also, when the pump is arrested, the liquid flows from one or both chambers back into and overflows from the tank so that the quantity of liquid decreases in response to each stoppage of the pump. Consequently, if the pump is repeatedly started and arrested, the overall quantity of liquid is likely to decrease below the lowermost points of the lower transporting rollers so that the liquid which flows from the orifices of the chambers and back into the tank is allowed to splash and to introduce into the main body of liquid large quantities of oxygen. Such liquid must be regenerated (or fresh developing liquid added) which contributes significantly to the cost of the developing operation. The addition of unlimited quantities of fresh developer is undesirable for the additional reason that the concentration of chemicals in the liquid bath changes with the result that the treatment of photographic material proceeds at an unpredictable rate.

In accordance with the disclosure in the aforementioned patent to Frick et al., the pipe which is connected with the overflow opening of the tank contains an electromagnetically operated valve which is closed in response to each stoppage of the pump so that the liquid which is returned from the chambers cannot escape from the tank, i.e., the level of liquid in the tank rises in automatic response to stoppage of the pump. Such a valve constitutes a potential source of malfunctioning. Moreover, the apparatus must employ a relatively large tank which should be capable of storing all of the liquid which is needed to insure that the lower transporting rollers dip into the body of liquid in the tank as well as that liquid which returns into the tank in response to stoppage of the pump, i.e., the liquid which is evacuated from the chambers by gravity flow. A tank which can store such large quantities of liquid when the pump is idle does not allow for rapid descent of liquid to an optimum level when the apparatus is in actual use.

SUMMARY OF THE INVENTION An object of the invention is to provide an apparatus for wet treatment of photographic material or the like with novel and improved means for regulating the level of processing liquid in the liquid storing vessel.

Another object of the invention is to provide a processing apparatus wherein the level of liquid in the vessel changes or fluctuates within a very narrow range in response to repeated starting or stoppage of the pump which supplies liquid to the chambers.

A further object of the invention is to provide the processing apparatus with novel means for controlling the overflow of liquid from the vessel and with novel means for introducing liquid into the chambers.

An additional object of the invention is to provide the processing apparatus with novel means for collecting the liquid which overflows from the tank.

The improved apparatus serves for wet treatment of strip material, particularly for development of exposed photographic films, and comprises liquid storing means (preferably a single vessel) having first and second compartments and being arranged to store a supply of processing liquid which overflows from the first into the second compartment when the first compartment is filled to a predetermined maximum level, a plurality of liquid discharging chambers which are preferably mounted on the storing meansso that at least a portion of the interior of at least one chamber is located above the maximum level of liquid in the first compartment, transporting means including groups of driven rollers which define for strip material a preferably horizontal elongated path extending between the chambers so that streams of liquid which are discharged through openings provided in the chambers can impinge upon both sides of strip material in the elongated path and the thus discharged liquid thereupon flows into the first compartment, preferably by flowing along the lower roller of each group of rollers to thus reduce the likelihood of splashing, especially if the lower rollers are mounted in such a way that each thereof permanently dips into the supply of liquid in the first compartment, and liquid circulating means including one or more pumps which can be operated to supply liquid from the first and second compartments to the liquid discharging chambers. The liquid storing capacity of the second compartment at least equals the capacity of that portion of one or more chambers which extends above the maximum liquid level in the first compartment so that the second compartment can store the liquid which overflows from the first compartment in response to each termination of operation of the circulating means and as a result of return flow of liquid into the first compartment from those portions of the chambers which are located above the maximum level of liquid in the first compartment.

The storing means preferably includes a third compartment which can receive liquid overflowing from the second compartment when the latter is filled to a predetermined maximum level which can be located at or below the maximum liquid level in the first compartment.

If the circulating means comprises several pumps, one of these pumps may constitute a jet pump which draws liquid from the second compartment and forces it into a conduit which connects the outlet of the main pump with one of the chambers.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved apparatus itself, however, both as to its construction and its mode of operations, together with additional features and advantages thereof, will be best understood upon perusal of the following detailed description of certain specific embodiments with reference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic longitudinal vertical sectional view of a processing apparatus which embodies the invention; and

FIG. 2 is a similar sectional view of a portion of a modified processing apparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIG. 1, there is shown a processing apparatus which comprises a liquid storing vessel 201 separably supporting a frame having two vertical platens or walls one of which is illustrated at 1. All such parts which are supported by the two platens are identical with the corresponding parts of the apparatus disclosed in U.S. Pat. No. 3,688,677 and are denoted by similar reference characters. These parts include a group of two rear transporting rollers 2, 3, a group of two front transporting rollers 4, 5, and two liquid discharging vessels 16, 17 which define an elongated channel 102. Photographic material is caused to advance along a horizontal path 100 which extends through the nip of the transporting rollers 2, 3, through the chamber 102, and through the nip of the transporting rollers 4, 5. The upper chamber 17 has an elongated slit-shaped orifice or opening l7e which discharges a stream of liquid against the upper side of photographic material in the path 100. The lower chamber 16 has a similar orifice or opening 16b which discharges a stream of liquid against the underside of the photographic material. The reference characters 16c, 16d denote liquid intercepting extensions of the chamber 16 which guide liquid issuing from the openings 16b, l7e and flowing off the strip material in the path 100 toward the peripheral surfaces of the lower transporting rollers 3 and 5. The manner in which the liquid streams which issue from the orifices or openings 16!), l7e treat the material in the path and flow back into the vessel 201 is the same as described in U.S. Pat. No. 3,688,677 to which reference may be had if necessary. This also applies for the manner in which the liquid streams are prevented from entraining excessive amounts of air into the main supply of liquid in the vessel 201.

The vessel 201 of FIG. 1 constitutes a superior substitute for the tank 12 which is shown in the drawing of U.S. Pat. No. 3,688,677. The interior of the vessel receives two risers 202, 203 which respectively serve to supply liquid to the chambers 16 and 17. The upper end of the riser 202 is automatically connected with a nipple 29 when the frame including the platen I is mounted on the vessel 201. The nipple 29 supplies liquid to the lower chamber 16. A'similar nipple (not shown in FIG. 1) is coupled to the upper end of the riser 203 and serves to supply liquid to the upper chamber 17. In fact, the two nipples can serve as a means for supporting the entire frame including the platen 1, transporting rollers 2-5,chambers l6, l7 and other elements which are mounted on the two platens of the frame.

The reference character 204 denotes a conduit which serves to deliver into the vessel 201 metered quantities of fresh developing liquid. Such liquid is supplied by a conventional regenerator (not shown). The arrangement is preferably such that the conduit 204 supplies fresh liquid at a rate which is proportional to the speed of transport of photographic material along the path 100 and hence to the throughput of the processing apparatus.

The risers 202 and 203 are connected with the outlet of a main pump 207 by means of conduits 205, 206. The inlet of the main pump 207 draws liquid from the vessel 201 by way of an outlet 2011a. The vessel 20] has a generally rectangular outline and has an internal wall 20lb over which the liquid can flow from a first compartment 201A (which receives the lower portions of the lower transporting rollers 3, 5) into a second compartment 208. The upper end face of the wall 20lb is located below the open top of the vessel 201. The compartment 208 includes a main portion located to the right of the wall 201!) and an upright duct 20le which communicates with the main portion by way of an aperture 201g provided in the lowermost part of the wall 2011b. The left-hand side of the duct 20le is bounded by a further wall 201d whose upper edge face is located at the level of the upper edge face of the wall 20 lb. The vessel 201 further comprises a third compartment 20le serving to receive liquid which overflows the wall 201d and to deliver the thus received liquid to a drain 201 f. The compartment 20le receives spent liquid and can deliver such liquid to the aforementioned regenerator or to another destination.

The compartment 208 occupies that portion of the interior of the vessel 201 which is not taken up by the frame including the platen 1 and by the parts which are mounted on this frame. The liquid-storing capacity of the compartment 208 equals or exceeds the capacity of those portions of the chambers l6, 17 which are located above the maximum liquid level in the compartment 201A when the apparatus is in use, i.e., when the main pump 207 supplies liquid to the risers 202 and 203. Such liquid level is shown at 209. The vessel 20] is further formed with an aerating aperture 201h which connects the duct 2010 and hence the atmosphere with the uppermost part of the main portion of the compartment 208; as shown, the aperture 201h is provided in the wall 201]). The walls 201m and 201n which bound the upper side of the compartment 208 slope downwardly in a direction away from the aerating aperture 201/z.

The lower right-hand portion of the vessel 201 is provided with a fluid-discharging outlet 208a which supplies liquid from the main portion of the compartment 208 to the suction inlet 2100 of a jet pump 210. The latter serves to feed liquid into the conduit 206 for delivery into the upper chamber 17.

The operation of the apparatus is as follows:

When the main pump 207 is idle, the liquid fills the main compartment 201A of the vessel 201 to the maximum level 209. The chamber or chambers 16, 17 above the maximum level 209 are empty. If the opera tor decides to start the main pump 207 in order to prepare the apparatus for treatment of photographic strip or sheet material, the pump 207 draws liquid from the compartment 201A of the vessel 201 by way of the outlet 20la and supplies pressurized liquid to the conduits 205, 206 for introduction into the chambers 16, 17 by way of the risers 202 and 203. If the vessel 201 would not receive any additional liquid and if the compartment 208 were omitted, the level of liquid in the compartment 201A would descend from 209 to 211. However, the jet pump 210 is set in operation in automatic response to flow of liquid in the conduit 206 so that the suction inlet 210a draws liquid from the outlet 208a (i.e., from the compartment 208) and delivers such liquid to one of the chambers 16, 17 (in the illustrated embodiment, the conduit 206 delivers liquid to the chamber 17 but it is equally possible to use the conduit 206 for delivery of liquid to the riser for the lower chamber 16). The level of liquid in the compartment 201A rises back to 209 with a delay which is function of the output of the jet pump 210. The level of liquid in the compartment 208 descends and reaches the lowermost level 212 when the liquid in the compartment 201A returns to the level 209. From there on, the supply of liquid in the compartment 201A remains unchanged (i.e., at 209).

If the operator thereupon introduces a strip of photographic material (e.g., a web of interconnected exposed photographic roll films) into the path 100, the emulsion of the strip is permeated with liquid and therefore entrains some of the liquid beyond the nip of the transporting rollers 4, 5. Some of the liquid evaporates due to the fact that the liquid is normally maintained at an elevated temperature. The thus evacuated and evaporated liquid must be replaced. Also, the apparatus must be provided with means which compensates for chemical exhaustion of developing liquid; all this is achieved by adding fresh liquid via conduit 204 at a rate which is proportional with the quantity of treated photographic material per unit of time (i.e., with the speed of material transport along the path 100 and with the overall area of treated material). It will be seen that the rate at which the conduit 204 admits regenerated liquid varies; however, the quantity of the thus admitted liquid suffices to insure that the compartment 201A is filled to the level 209 and that some of the liquid overflows the wall 201b to enter the main portion of the compartment 208 by way of the duct 201c and aperture 2013. Therefore, the level of liquid in the compartment 208 rises. When the apparatus is in use for an extended period of time, the compartment 208 is gradually filled to capacity and the surplus liquid overflows the wall 210d to enter the compartment 20le so that it can be recirculated to the regenerator by way of the drain 20lf. Thus, once the compartment 208 is filled, the vessel 201 discharges spent liquid substantially at the same rate (via drain 20 If) at which the conduit 204 admits regenerated liquid. The main pump 207 continues to draw liquid from the compartment 201A (via outlet 201a) and the jet pump 210 continues to draw liquid from the compartment 208 (by way of the outlet 208a).

The main pump 207 need not be turned off during relatively short-lasting interruptions in the transport of photographic material along the path 100. However, the pump 207 will be turned off when the interruption is relatively long. The liquid which has filled the chambers l6, 17 then returns into the vessel 201 by gravity flow, in part through the pump 207 and in part by flowing along the lower transporting rollers 3, 5. Since the compartment 201A is filled to capacity, the liquid which is discharged by the vessels 16, 17 following a stoppage of the main pump 207 overflows the wall 201d and leaves the vessel 201 by way of the drain 20 l f (provided that the compartment 208 is also filled with liquid).

The aforedescribed procedure is repeated when the main pump 207 is started, i.e., the pump 207 then draws liquid from the compartment 201A so that the level of liquid therein descends below 209 but the jet pump 210 draws liquid from the compartment 208 to compensate for the liquid which is being withdrawn from the compartment 201A so that the liquid level rises back to 209. The conduit 204 begins to supply regenerated liquid as soon as the operator begins with the admission of photographic material into the path 100. As explained above, the conduit 204 thereupon insures that the compartment 201A remains filled to the level 209 regardless of the amounts of liquid which are being withdrawn by photographic material and/or escape from the vessel 201 due to evaporation.

FIG. 2 illustrates a portion of a modified processing apparatus wherein all such parts which are identical with or clearly analogous to the parts shown in FIG. 1 are denoted by similar reference characters. An important difference between the apparatus of FIGS. 1 and 2 is that the latter can operate properly without the jet pump 210 or another auxiliary pump because the outlet 2080 is connected with the inlet of the pump 207 so that the latter draws liquid from the compartment 201A as well as from the compartment 208.

The apparatus of FIG. 2 further comprises an automatic valve which controls the outflow of liquid from the compartment 201A by way of the outlet 2010. This valve comprises a valve member 215 at the upper end of the outlet 201a and a float 213 which is connected with the valve member 215 by a shank or stem 214.

The float 213 swims on or in the body of liquid in the compartment 201A. The length of the stem 214 is selected in such a way that the valve member 215 allows for unimpeded outflow of liquid by way of the outlet 201a when the liquid fills the compartment 201A to the level 209. When the supply of liquid in the compartment 201A sinks well below the level 209, the valve member 215 at least partially seals the outlet 201a to prevent or to interfere with further evacuation of liquid. It will be noted that the cross-sectional area of the outlet 208a is much smaller than that of the outlet 2010.

The operation of the apparatus of FIG. 2 is analogous to that of the first apparatus. The main difference is that the pump 207 normally draws liquid mainly from the compartment 201A so that the level of liquid in this compartment rapidly descends with the result that the float 213 allows the valve member 215 to seal or nearly seal the outlet 201a. From there on, the pump 207 draws liquid mainly from the compartment 208 by way of the outlet 208a. The level of liquid in the compartment 201A thereupon remains unchanged until after complete filling of the chambers 16 and 17 (not shown in FIG. 2). Once the two chambers are filled with liquid, the level of liquid in the compartment 201A begins to rise so that the float 213 allows the outlet 201a to supply liquid to the pump 207 at an increasing rate. When the valve including the parts 213-2l5 is fully open, the ratio of liquid which is being withdrawn from the compartment 201A to liquid which is being withdrawn from the compartment 208 equals the ratio of the cross-sectional areas of the outlets 201a and 208a. In other words, the outlet 208a acts not unlike a flow restrictor or throttle to insure that the recirculation of liquid in the compartment 201A is more pronounced than that in the compartment 208.

An advantage of the processing apparatus of FIG. 2 is that the two risers 202, 203 can receives identical quantities of liquid. This is due to the fact that the cross-sectional area of the passage between the outlet of the pump 207 and one of the chambers 16, 17 need not be reduced in a manner as shown in FIG. 1 for the conduit 206 (due to the provision of jet pump 210).

An advantage of the apparatus of FIG. 1 is that the level at which liquid overflows from the compartment 208 (over the wall 201d) need not be located at the level (209) at which the liquid overflows from the compartment 201A. However, if the upper edge face of the wall 201d is located below the upper edge face of the wall 201b (see 201d in FIG. 1), the apparatus of FIG. I must be provided with a check valve 216 (indicated by broken lines) which can be installed between the jet pump 210 and the outlet 20811 to prevent liquid from leaving the vessel 201 by way of the drain 201f when the pump 207 of FIG. 1 is idle. This will be readily appreciated by considering that, if the upper edge face of the wall 201d is located at a level below the upper edge face of the wall 201b (as shown at 201d) and the pump 207 is idle (and assuming that the check valve 216 is omitted), liquid can flow from the compartment 201A, via outlet 201a, main pump 207, conduit 206 and jetpump 210, inlet 210a, outlet 208a, main portion of the compartment 208, apertures 201g, 201k, duct 201e, over the wall 201d, compartment 2012 and into the drain 20 1 f. The escape of liquid is terminated when the level of liquid in the compartment 201A descends to match the level of the upper edge face of the wall 201d.

The improved apparatus is susceptible of many additional modifications without departing from the spirit of the invention. For example, the vessel 201 need not be of rectangular or other polygonal outline. Also, the vessel 201 may be replaced with a vessel having twin walls so that the compartment corresponding to the compartment 208 surrounds the compartment corresponding to the compartment 201A. The arrangement which is shown in the drawing is preferred at this time because the walls 201m, 201n which slope toward the aerating aperture 20lh insure that no air can be entrapped in the compartment 208, i.e., such construction of the vessel reduces the likelihood of premature oxidation of the liquid. In each embodiment of the improved apparatus, the liquid storing capacity of the compartment 208 should equal or exceed the combined liquid storing capacity of those portions of the chambers 16, 17 which are located above the liquid level when the apparatus is idle. This insures that the compartment 208 can store the liquid which leaves the two chambers in response to stoppage of the pump 207.

The compartment 208 should be at least partially filled with liquid at all times, i.e., during operation as well as when the pump 207 is idle. This prevents the jet pump 210 of FIG. 1 from drawing air by way of the outlet 208a; such air would be intimately admixed to liquid in the conduit 206 and riser 203 and would promote oxidation.

It is further within the purview of the invention to provide in the vessel a liquid displacing body whose volume can be changed to an extent which at least equals but preferably exceeds the space requirements of that liquid which is being discharged from the chambers 16, 17 in response to stoppage of the pump. For example, such body may constitute a rubber balloon which can be expanded by resorting to a small compressor which feeds into it a compressed gas. The compressor is set in operation together with the pump 207 so that the balloon expands and displaces a certain amount of liquid. When the pump 207 is arrested, the compressor is also arrested and the balloon is caused or allowed to shrink at the rate at which the two chambers discharge liquid into the vessel. This prevents the liquid from overflowing the vessel in response to stoppage of the pump. The compressor is started again in response to renewed starting the pump to thus reduce the liquidstoring capacity of the vessel by an amount which equals the combined liquid-storing capacity of the two chambers. This insures that the level of liquid in the main compartment of the vessel fluctuates very little or not at all, even during starting or stoppage of the pump.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features which fairly constitute essential characteristics of the generic and specific aspects of our contribution to the art and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:

1. In an apparatus for wet treatment of strip material, particularly for development of exposed photographic films, a combination comprising liquid storing means having first and second compartments and arranged to store a supply of processing liquid which overflows from said first into said second compartment when said first compartment is filled to a predetermined maximum level; a plurality of liquid discharging chambers mounted on said storing means so that at least a portion of at least one of said chambers is located above said maximum level; transporting means including groups of driven rollers defining for strip material an elongated path extending between said chambers, said chambers having openings arranged to discharge streams of processing liquid against both sides of strip material in said path whereby the major part of the thus discharged liquid flows into said first compartment; and liquid circulating means operable to supply liquid simultaneously from said first and second compartments into said chambers, the liquid storing capacity of said second compartment being at least equal to the capacity of said portion of said one chamber so that said second compartment can store the liquid which overflows from said first compartment in response to termination of operation of said circulating means and as a result of return flow of liquid from said portion of said one chamber into said first compartment.

2. A combination as defined in claim 1, wherein each of said groups of rollers includes a lower roller dipping into the supply of liquid in said first compartment and further comprising liquid intercepting means arranged to direct said liquid streams against said lower rollers so that said streams return into said first compartment without appreciable splashing.

3. A combination as defined in claim 1, wherein said circulating means comprises a jet pump.

4. A combination as defined in claim 1, wherein said first and second compartments respectively have first and second outlets and said circulating means comprises a pump having an inlet connected with said first and second outlets and an outlet connected with said chambers 5. A combination as defined in claim 1, wherein said storing means includes a single vessel including wall means separating said first compartment from said second compartment.

6. A combination as defined in claim 1, further comprising means for supplying measured quantities of fresh liquid to at least one of said compartments.

7. In an apparatus for wet treatment of strip material, particularly for development of exposed photographic films, a combination comprising liquid storing means having first, second and third compartments and arranged to store a supply of processing liquid which overflows from said first into said second compartment when said first compartment is filled to a first predetermined maximum level and from said second compartment into said third compartment when said second compartment receives liquid while being filled to a second predetermined maximum level; a plurality of liquid discharging chambers mounted on said storing means so that at least a portion of at least one of said chambers is located above said first maximum level; transporting means including groups of driven rollers defining for strip material an elongated path extending between said chambers, said chambers having openings arranged to discharge streams of processing liquid against both sides of strip material in said path whereby the major part of the thus discharged liquid flows into said first compartment; and liquid circulating means operable to supply liquid from said first and second compartments into said chambers, the liquid storing capacity of said second compartment being at least equal to the capacity of said portion of said one chamber so that said second compartment can store the liquid which overflows from said first compartment in response to termination of operation of said circulating means and as a result of return flow of liquid from said portion of said one chamber into said first compartment.

8. A combination as defined in claim 7, wherein said second maximum level coincides with or is closely adjacent to said first mentioned maximum level.

9. A combination as defined in claim 7, wherein said second maximum level is located below said first mentioned level, said second compartment having an outlet and said circulating means including a conduit connected with said outlet, and further comprising a check valve provided in said conduit to prevent the flow of liquid from said first compartment when said circulating means is idle.

10. In an apparatus for wet treatment of strip material, particularly for development of exposed photographic films, a combination comprising liquid storing means having first and second compartments and arranged to store a supply of processing liquid which overflows from said first into said second compartment when said first compartment is filled to a predetermined maximum level; a plurality of liquid discharging chambers mounted on said storing means so that at least a portion of at least one of said chambers is located above said maximum level; transporting means including groups of driven rollers defining for strip material an elongated path extending between said chambers, said chambers having openings arranged to discharge streams of processing liquid against both sides of strip material in said path whereby the major part of the thus discharged liquid flows into said first compartment; and iquid circulating means operable to supply liquid from said first and second compartments into said chambers, the liquid storing capacity of said second compartment being at least equal to the capacity of said portion of said one chamber so that said second compartment can store the liquid which overflows from said first compartment in response to termination of operation of said circulating means and as a result of return flow of liquid from said portion of said one chamber into said first compartment, said circulating means comprising a first pump having an inlet receiving liquid from said first compartment and an outlet, a plurality of conduits connecting said outlet with said chambers, and a jet pump installed in one of said conduits and having an inlet receiving liquid from said second compartment.

11. In an apparatus for wet treatment of strip material, particularly for development of exposed photographic films, a combination comprising liquid storing means having first and second compartments and arranged to store a supply of processing liquid which overflows from said first into said second compartment when said first compartment is filled to a predetermined maximum level, said first and second compartments respectively having first and second outlets; a plurality of liquid discharging chambers mounted on said storing means so that at least a portion of at least one of said chambers is located above said maximum level; transporting means including groups of driven rollers defining for strip material an elongated path extending between said chambers, said chambers having openings arranged to discharge streams of processing liquid against both sides of strip material in said path whereby the major part of the thus discharged liquid flows into said first compartment; liquid circulating means operable to supply liquid from said first and second compartments into said chambers, the liquid storing capacity of said second compartment being at least equal to the capacity of said portion of said one chamber so that said second compartment can store the liquid which overflows from said first compartment in response to termination of operation of said circulating means and as a result of return flow of liquid from said portion of said one chamber into said first compartment, said circulating means comprising a pump having an inlet connected with said first and second outlets and an outlet connected with said chambers; and flow restrictor means provided between said second compartment and said pump.

12. A combination as defined in claim 11, wherein said flow restrictor means is said second outlet.

13, In an apparatus for wet treatment of strip material, particularly for development of exposed photographic films, a combination comprising liquid storing means having first and second compartments and arranged to store a supply of processing liquid which overflows from said first into said second compartment when said first compartment is filled to a predetermined maximum level, said first and second compartments respectively having first and second outlets; a plurality of liquid discharging chambers mounted on said storing means so that at least a portion of at least one of said chambers is located above said maximum level; transporting means including groups of driven rollers defining for strip material an elongated path extending between said chambers, said chambers having openings arranged to discharge streams of processing liquid against both sides of strip material in said path whereby the major part of the thus discharged liquid flows into said first compartment; liquid circulating means operable to supply liquid from said first and second compartments into said chambers, the liquid storing capacity of said second compartment being at least equal to the capacity of said portion of said one chamber so that said second compartment can store the liquid which overflows from said first compartment in response to termination of operation of said circulating means and as a result of return flow of liquid from said portion of said. one chamber into said first compartment, said circulating means comprising a pump having an inlet connected with said first and second outlets and an outlet connected with said chambers; and valve means arranged to reduce the rate of flow of liquid by way of said first outlet when the supply of liquid in said first compartment descends below said maximum level.

14. A combination as defined in claim 13, wherein said valve means includes a float swimming in the supply of liquid in said first compartment.

15. In an apparatus for wet treatment of strip material, particularly for development of exposed photographic films, a combination comprising liquid storing means having first and second compartments and arranged to store a supply of processing liquid which overflows from said first into said second compartment when said first compartment is filled to a predetermined maximum level, said storing means including a single vessel having wall means separating said first compartment from said second compartment, said second compartment including an uppermost portion and said vessel further having an aerating opening allowing for the flow of air between said uppermost portion of said second compartment and the atmosphere, said .wall means sloping downwardly from said aerating opening; a plurality of liquid discharging chambers mounted on said storing means so that at least a portion of at least one of said chambers is located above said maximum level; transporting means including groups of driven rollers defining for strip material an elongated path extending between said chambers, said chambers having openings arranged to discharge streams of processing liquid against both sides of strip material in said path whereby the major part of the thus discharged liquid flows into said first compartment; and liquid circulating means operable to supply liquid from said first and second compartments into said chambers, the liquid storing capacity of said second compartment being at least equal to the capacity of said portion of said one chamber so that said second compartment can store the liquid which overflows from said first compartment in response to termination of operation of said circulating means and as a result of return flow of liquid from said portion of said one chamber into said first compartment. 

1. In an apparatus for wet treatment of strip material, particularly for development of exposed photographic films, a combination comprising liquid storing means having first and second compartments and arranged to store a supply of processing liquid which overflows from said first into said second compartment when said first compartment is filled to a predetermined maximum level; a plurality of liquid discharging chambers mounted on said storing means so that at least a portion of at least one of said chambers is located above said maximum level; transporting means including groups of driven rollers defining for strip material an elongated path extending between said chambers, said chambers having openings arranged to discharge streams of processing liquid against both sides of strip material in said path whereby the major part of the thus discharged liquid flows into said first compartment; and liquid circulating means operable to supply liquid simultaneously from said first and second compartments into said chambers, the liquid storing capacity of said second compartment being at least equal to the capacity of said portion of said one chamber so that said second compartment can store the liquid which overflows from said first compartment in response to termination of operation of said circulating means and as a result of return flow of liquid from said portion of said one chamber into said first compartment.
 2. A combination as defined in claim 1, wherein each of said groups of rollers includes a lower roller dipping into the supply of liquid in said first compartment and further comprising liquid intercepting means arranged to direct said liquid streams against said lower rollers so that said streams return into said first compartment without appreciable splashing.
 3. A combination as defined in claim 1, wherein said circulating means comprises a jet pump.
 4. A combination as defined in claim 1, wherein said first and second compartments respectively have first and second outlets and said circulating means comprises a pump having an inlet connected with said first and second outlets and an outlet connected with said chambers.
 5. A combination as defined in claim 1, wherein said storing means includes a single vessel including wall means separating said first compartment from said second compartment.
 6. A combination as defined in claim 1, further comprising means for supplying measured quantities of fresh liquid to at least one of said compartments.
 7. In an apparatus for wet treatment of strip material, particularly for development of exposed photographic films, a combination comprising liquid storing means having first, second and third compartments and arranged to store a supply of processing liquid which overflows from said first into said second compartment when said first compartment is filled to a first predetermined maximum level and from said second compartment into said third compartment when said second compartment receives liquid while being filled to a second predetermined maximum level; a plurality of liquid discharging chambers mounted on said storing means so that at least a portion of at least one of said chambers is located above said first maximum Level; transporting means including groups of driven rollers defining for strip material an elongated path extending between said chambers, said chambers having openings arranged to discharge streams of processing liquid against both sides of strip material in said path whereby the major part of the thus discharged liquid flows into said first compartment; and liquid circulating means operable to supply liquid from said first and second compartments into said chambers, the liquid storing capacity of said second compartment being at least equal to the capacity of said portion of said one chamber so that said second compartment can store the liquid which overflows from said first compartment in response to termination of operation of said circulating means and as a result of return flow of liquid from said portion of said one chamber into said first compartment.
 8. A combination as defined in claim 7, wherein said second maximum level coincides with or is closely adjacent to said first mentioned maximum level.
 9. A combination as defined in claim 7, wherein said second maximum level is located below said first mentioned level, said second compartment having an outlet and said circulating means including a conduit connected with said outlet, and further comprising a check valve provided in said conduit to prevent the flow of liquid from said first compartment when said circulating means is idle.
 10. In an apparatus for wet treatment of strip material, particularly for development of exposed photographic films, a combination comprising liquid storing means having first and second compartments and arranged to store a supply of processing liquid which overflows from said first into said second compartment when said first compartment is filled to a predetermined maximum level; a plurality of liquid discharging chambers mounted on said storing means so that at least a portion of at least one of said chambers is located above said maximum level; transporting means including groups of driven rollers defining for strip material an elongated path extending between said chambers, said chambers having openings arranged to discharge streams of processing liquid against both sides of strip material in said path whereby the major part of the thus discharged liquid flows into said first compartment; and iquid circulating means operable to supply liquid from said first and second compartments into said chambers, the liquid storing capacity of said second compartment being at least equal to the capacity of said portion of said one chamber so that said second compartment can store the liquid which overflows from said first compartment in response to termination of operation of said circulating means and as a result of return flow of liquid from said portion of said one chamber into said first compartment, said circulating means comprising a first pump having an inlet receiving liquid from said first compartment and an outlet, a plurality of conduits connecting said outlet with said chambers, and a jet pump installed in one of said conduits and having an inlet receiving liquid from said second compartment.
 11. In an apparatus for wet treatment of strip material, particularly for development of exposed photographic films, a combination comprising liquid storing means having first and second compartments and arranged to store a supply of processing liquid which overflows from said first into said second compartment when said first compartment is filled to a predetermined maximum level, said first and second compartments respectively having first and second outlets; a plurality of liquid discharging chambers mounted on said storing means so that at least a portion of at least one of said chambers is located above said maximum level; transporting means including groups of driven rollers defining for strip material an elongated path extending between said chambers, said chambers having openings arranged to discharge streams of processing liquid against both sides of strip matErial in said path whereby the major part of the thus discharged liquid flows into said first compartment; liquid circulating means operable to supply liquid from said first and second compartments into said chambers, the liquid storing capacity of said second compartment being at least equal to the capacity of said portion of said one chamber so that said second compartment can store the liquid which overflows from said first compartment in response to termination of operation of said circulating means and as a result of return flow of liquid from said portion of said one chamber into said first compartment, said circulating means comprising a pump having an inlet connected with said first and second outlets and an outlet connected with said chambers; and flow restrictor means provided between said second compartment and said pump.
 12. A combination as defined in claim 11, wherein said flow restrictor means is said second outlet.
 13. In an apparatus for wet treatment of strip material, particularly for development of exposed photographic films, a combination comprising liquid storing means having first and second compartments and arranged to store a supply of processing liquid which overflows from said first into said second compartment when said first compartment is filled to a predetermined maximum level, said first and second compartments respectively having first and second outlets; a plurality of liquid discharging chambers mounted on said storing means so that at least a portion of at least one of said chambers is located above said maximum level; transporting means including groups of driven rollers defining for strip material an elongated path extending between said chambers, said chambers having openings arranged to discharge streams of processing liquid against both sides of strip material in said path whereby the major part of the thus discharged liquid flows into said first compartment; liquid circulating means operable to supply liquid from said first and second compartments into said chambers, the liquid storing capacity of said second compartment being at least equal to the capacity of said portion of said one chamber so that said second compartment can store the liquid which overflows from said first compartment in response to termination of operation of said circulating means and as a result of return flow of liquid from said portion of said one chamber into said first compartment, said circulating means comprising a pump having an inlet connected with said first and second outlets and an outlet connected with said chambers; and valve means arranged to reduce the rate of flow of liquid by way of said first outlet when the supply of liquid in said first compartment descends below said maximum level.
 14. A combination as defined in claim 13, wherein said valve means includes a float swimming in the supply of liquid in said first compartment.
 15. In an apparatus for wet treatment of strip material, particularly for development of exposed photographic films, a combination comprising liquid storing means having first and second compartments and arranged to store a supply of processing liquid which overflows from said first into said second compartment when said first compartment is filled to a predetermined maximum level, said storing means including a single vessel having wall means separating said first compartment from said second compartment, said second compartment including an uppermost portion and said vessel further having an aerating opening allowing for the flow of air between said uppermost portion of said second compartment and the atmosphere, said wall means sloping downwardly from said aerating opening; a plurality of liquid discharging chambers mounted on said storing means so that at least a portion of at least one of said chambers is located above said maximum level; transporting means including groups of driven rollers defining for strip material an elongated path extending between said chambers, said chambers hAving openings arranged to discharge streams of processing liquid against both sides of strip material in said path whereby the major part of the thus discharged liquid flows into said first compartment; and liquid circulating means operable to supply liquid from said first and second compartments into said chambers, the liquid storing capacity of said second compartment being at least equal to the capacity of said portion of said one chamber so that said second compartment can store the liquid which overflows from said first compartment in response to termination of operation of said circulating means and as a result of return flow of liquid from said portion of said one chamber into said first compartment. 